Xslide-valve m mechanism



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C. SCEMD). SLIDE VALVE MBGHANISM. No. 423,492. i Patented Mam. 18, 1890.

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C. SGHMID. SLIDE VALVE MEGHANISM. No. 423,492. Patented Mar. 18, 1890.

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o. SGHMID. SLIDE VALVE MEOHANISM.

(No Model.)

No. 423,492. Patented Mar. 18,1890,

N. PETERS. Fhnxo-Lnhographu, wasmnglon. D. Q

UNITED STATES PATENT Orrlcn.

CHARLES SCHMID, OF CHICAGO, ILLINOIS.

SLIDE-VALVE MEcHANlsM.

SPECIFICATION forming part of Letters Patent No. 423,492, dated March 18, 1890.

Application filed J une 2, 1887 Serial No.A 240,024. (No model.)

vclass of slide-valve mechanism for steam-engines setoutin the Letters Patentof the United States Nos. 337,441 and 347,012, granted to myself and George Farnsworth on March 9, 1886, and August 10, 1886, respectively. In

' the construction of valve mechanism set forth in said patents the main slide-valve was provided with escape or exhaust ports adapted to'be brought coincident with the usual steamways of the main cylinder, the passage of the steam through these ports being controlled by means of a supplemental valve placed within a chamber of the main slide-valve, which chamber communicated with the usual exhaust-cavity of the cylinder, and the position of the supplemental valve with respect to the escape and exhaust ports ofj-the main valve was determined by a connection between said supplemental valve andfrits steamchest, so that the position of the supplemental valve with respect to the ports of the main valve was shifted at each movement of the main valve. The 4object of the inventions deiined in said patents was to lessen the backpressure or resistance in the cylinder upon the exhaust side of' the piston, so that the loss of energy and consequent increase of working cost incident to such resistance would be avoided. In my present construction of valve mechanism the main slide valve is also provided with escape or exhaust ports, the passage of steam through which is controlled by a supplemental valve, the position of this valve with respect to the ports of the main valve being shifted or changed at each movement of the latter; butin this construction I have modified the mechanism whereby the shift or change of the position of the supplemental valve with. respect to the main valve is effected, and have modified, also, in

various respects, hereinafter noted, the relative arrangement of the main and supplemental valves.

My present invention consists in the various novel features of construction hereinafter described, illustrated in the accompanying drawings, and particularly deiined in the claims at the end of this specification.

Figure 1 is a View in central'longitudinal section on line x of Fig. 5. Figs. 2, 3, and 4 are views similar to Fig. 1, but showing the parts in different-positions during t-he action of the valve. Fig. 5 is a plan'view of my iinproved valve mechanism, the cover of the slide-valve being omitted. Fig. 6 is a View in vertical cross-section on line y y of Fig.

5. Fig. 7 is an inverted plan view' of the main valve. Fig. 8 is a fractional plan view (reduced scale) of a modified form of connection for the supplemental valve. Fig. 9 is a view, partly in section and partly in side elevation, showing the combination of the valve with variable cut-off.

A designates the main cylinder of the engine, provided with the usual steamways a and ct and exhaust-port a2, and B denotes the steam-chest, within Which, upon its appropriate seat, is placed the main slide-valve, that is operated in the usual manner by the valve-rod C, the yoke c of vwhich embraces the valve. The body of the main slide-valve (like that in` Patent No. 3f? ,012) is preferably cast in such manner as to `form the outer walls or sides D' in single piece with the portplate D and the cavity plate or roof D2, these plates being connected together by the end plates or ribs d, which extend between them at the ends of the long valve-chamber ports d and d2. The main slide-valve is provided with the usual exhaust-cavity d3, that extends from side to side of the valve, as seen in Fig.-

6, and at its ends this cavity communicates by the ports d4 and d5 with the exhaust-chamber E, formed inthe upper portion of the main valve by the walls D, the cover D4, that is suitably bolted to said Walls, and by the portplate D. Beneath the port-plate D', and on opposite sides of the central rib D5 and cavity plate or roof D2, are preferably formed the expanded steam-spaces F and F, that are IOO connected at their top with the valve-chamber E by means of the valve-ports d and d2 these strips overlap the reduced ends h of the.

supplemental valve H and serve to hold this valve in proper bearing upon the port-plate as the main slide-valve is moved. Upon the upper face of the supplemental valve H are preferably formed the lugs or standards K, having sockets or seats k formed therein to receive the'rods L, which are held in fixed position with respect to the supplemental valve by means of the split collars Z, that encircle the rods adjacent the lugs or standards K, and are iirmly clamped therein by the.

screws l', passing through their ends. The rods L, vas shown in Fig. 5, pass through the end Walls of the main slide-valve, and in this specific construct-ion are conveniently attached tothe steam-chest by means ofthe plates M, bolted thereto, as seen at m. If desired, stuffing-boxes O, of usual or suitable' construction, may be fitted in the perforations of the slide-valve .that receives the rods L, and by this means all danger of the leakage of steam from the steam-chest into the chamber of the main valve willbe avoided. l

From the foregoing description the operation vof the mechanism will be seen to be as follows: Assume the parts to be in the relative position shown in Fig. 1, with the main slide-valve traveling in the direction of. the arrow. At this instant live steam is being admitted from the steam-chest through the steamway a into the cylinder behind the pis- -ton W and the exhaust-steam is passing from theexhaust end ofthe cylinder through the steamway a', and thence in part through the exhaust-cavity d?"` and exhaust-port a2 of the cylinder and in part through the escape-port Y d', the steam-space-F',and the escape-port d2 into the chamber E of the valve, and thence through the ports d4 and d5 into the exhaustcavity cl3. As the valve continues to be moved in the direction of the arrow, Fig. l, live steam will continue to 'pass through the steamway a into the cylinder, vand will exhaust in the manner above specified until the lap-plate G has passed beyond the port of the steamway d', as seen in Fig. 2, at which time the entire exhaust will occur directly from the steamwayra into the exh aust-.cavity d3. From the position of the parts in Fig. 1 itwill be seen that if the valve were of ordinary construction-that is to say, without exhaustor escape ports formed therein-the ventire exhaust at the beginning of the stroke would occur through` the narrow space between the steamway a' and the exhaust-cavity d3; but by providing the main slide-valve with the exhaust ports formed through the same itis obvious that I double the area of the exhaust, since it is plainV that iny addition to the direct exhaust from the steamway a' into the cavity d3, I obtain apassage of equal area for the exhaust v steam through the exhaust orescape ports e' steamspace F', and port d2. itwill be seen that the port CZ' in the portplate D' does not pass from beneath the supplemental valve until the lap-plate 'G passes off the. bridge adjacent the steamway c, and hence the release of the steam through the port d and exhaust or escape porte does not occur any sooner than thedirect release through the port of the steamway a' and exhaust-cavity d3. When the main .valve, after being moved to open the steamway a, returns to a point Aslight- 1y beyond the p'osition'shown in Fig. l, the communication between the steam-chest and the By reference to Fig. 3

steamway awillbe cut oft and the steam will be allowed to act expansively in the cylinder until the valve reaches the position shown in Fig. 3, when the release of the steam will occur.

escape of the exhaust-steam from the cylinder Will be Vhad from the steamway` a in part cape ports of the main valve.l In other Words,`

while obtaining the advantage of the inside lap-plates G and G', I avoid the disadvantage ,incident to the employment of inside lap in ordinary valves, and it is wellknown that in the ordinary construction of slide-valves the use of inside lap so shortens the periodA of exhaust, by .obstructing the steamways `of the cylinder, that for this reason no inside lap (or a triiiing amount only) is usually given to valves` for engines-such, for example, as. locomotives-which run at high rates of speed, and` in which ,the valves consequently work Withveryjshort stroke.v With my above-described form of valve; however, it isn obvious that no matter how short `may be the stroke of the valve an amplefexhaust of the steam will be attained, as the stroke will always be sufcient to uncoverthe exhaust-ports d' and cl2, and, while there will be a period (shortly after .the steam has been cut off and before the release during which there Will be no From Fig. l it willbe seen that atthe moment that the steam' is thus cut off a free ,9S directly through the exhaust-cavity d? and in4 IOO IIO

exhaust from the vrcylinder, still it will be. I

found that the full exhaust already permitted will have allowed so much of the steamlto escape that the exhaust-steam remaining in the cylinder will causeno material loss of energy. y

InFig. 4 the parts are shown in the position thereverse ofy that yillustrated in Fig. l'-

that is to say, at the beginning of t-he admission ofv steam through the steamway a and its exhaust through the steamway a. 'It is 'y obvious that when the steam is thus admitted to the cylinder through the steamway a the exhaust-steam Vpassin g through 'the steamwayl a 'will escape in p'artdire'ctlythrough the exhaust-cavity (Z5 and in part through the es'-` cape or exhaust ports el, the 'ports cl', the cham'- ber E, and thence'through the exhaust-ports' d* and d5 to the exhaust-cavity d3. It Willbe seen that during this back-and-forth move` ment of the main 'valvethe. supplemental valve H Willbe held in ixe'd 'position by the rods L, and the shiftor change of the relative position of the main and supplemental valvesV Willocc'ur at such time that when the live steam is being admitted.- through the steam- Way a' to the main slide-valve the exhaustport d of the port-plate D will be closed,and

' whenlive steam is being admittedthrough the steamway ct (see Fig. 4) the-exhaust-port (Z2 in the port-plate D will be closed,`and hence steam through these ports until such release occursdirectly through the steamways and ports d and d2.

the 'exhaust-cavity cl3, and by forming the supplemental valve of such Width that it Will overlap (that is to say, will have flap) the the steam through these escape-ports e and e will be correspondinglyprolonged, and in the construction shown the supplemental valve is provided with a' lap equal to the inside lap of the main valve, and hence, as seen by Fig. 3, the release of the steam will occur simultaneously directly through the exhaust-cavity cl3 and through the escape-ports d.

By reference to Fig. 7 of the drawings it will be seen that the escape or exhaust ports e and e extend from end to end of the main valve, with the exception of the thickness of the end Walls, and hence extend opposite the ports d* and d5, which lead from the valvechamber E into the usual exhaust-cavity cl3. My purpose in giving to' these ports e and e this increased length is to correspondingly increase the area of the exhaust-ports e and e', so that when the valve is Working with a short stroke a freer exhaust will be had through these ports. A further advantage, which I believev to be incident to forming the exhaust-ports e and e of considerable area, and as Well, also, to forming the valve with the steam-spaces F and F is that the compression from theexhaust side of the cylinder, after the port cl2 has been closed, exerting pressure upon the port-plate D', Will-tend to slightly lift or balance the main valve, and hence relieve in a measure its friction upon the Valve-seat. Moreover, when the' rods L are extended through the Walls D of the main valve and fastened to the steamchest these rods will also serve to relieve the pressure of the main valve upon its seat, and

The delay in the release ofi Will hence operate in 'a measure to balanceI the .nia-in valve. L Y l In the modified construction illustrated in- Fig. 7 of the drawings I have' shown asingle rod L, connecting the supplemental valve H with the steam-chest, and in -this constructionthis rodiDisalso shown as connected with the steam-chest at one end only. This modification is evidently Withinthe scopeof my present invention, although I do not regard it as so desirable an embodiment thereof as the form previously described.

My present construction of valve mechanism, aswell as that set forth in my prior patents above referred to,I have found most applicable for use in connection with variable cut-off mechanism--such, for example, as a link-motion, commonlyemployed onv locomotives-or a valve-gear governor-fsuch, f or example, as the Well-known slotted eccentricgovernor-and in Fig. 8 of the drawings I .have illustrated myinvention as applied. to

the well-known form of link-motion monly used upon locomotives.

Referring to Fig. 8, the valve-rod C is shown as connected to the upper end of the rocker CO m' R, that is pivoted in the usual manner tothe rocker-shaft S, the lowerarm'of this rocker being connected in the usual manner with the block T, that slides Within the slotted link V, to which movement is imparted by the 'eccentric-rods V and V2 fromthe usual eccentrics. The position of the link VV Will be shifted in Well-known manner, either automatically, if a governor be employed, or by hand, if a rcverse-rod be employed, as in a locomotive. It Will be found that when the position of the link is shifted, in order to vary the stroke of the main slide-valve, the position of the v'sup- IOO plemental valve With respect to the escape- Y p orts of the main valve Will be so determined by the connection of the supple-mental valveV to the steam-chest that even when a very short stroke is given to the main valve the escape or exhaust ports of the main valvetvill be uncovered in such manner as to permit a free lescape of the exhaust-steam through these ports.

In Fig. 8 of the drawings, Where the main valve is shown as making a very short stroke, it will be seen that escape or exhaust port d2 is Wide open, thus permittinga free escape of steam through this port into'the chamber of the main valve. While I have shovvn but one form of variable cut-off, (bywhich term I mean any suit-able mechanism for varying the stroke of the main valve,) it is obvious that it Will be Within the scope of my invention to employ other forms of variable cut-ois-such as a governorfwithout departing fromthe scope of the invention. 4 p

Having thus described my invention, What I claim as new, and' desire to secure ,byl Letters Patent, isn s l. In slide-valve mechanism, the combination, with the main slide-valve havingescape or exhaust ports therein and a supplemental IIO . ing the movement of the main slide-valve,

substantially as described.

3. In slide-valve mechanism', the combination, with the chambered slide-valve havingv escape-ports therein,of a supplemental valve anda fixed connection extending between said supplemental valve and the steam-chest, said connection serving to hold the supplemental valve during the movement of the main valve, substantially as described.

4. In slide-valve mechanism,l the combination, -with the main chambered slide-valve having escape-ports therein, .of a supplemental valve ,and a rod or rods extending through the main slidevalve,-sa id rod or rods being connected with the supplemental valve and to some relatively liixed part of the engine structure, substantially as described.

5. `In slide-valve mechanism, the combination, with the main slide-valve having escape-ports therein, of a supplemental valve for said escape-ports, said supplemental valve being of sulicient width to cover the escapeports immediately beneath it, and suitable mechanism controlling the position of said supplemental valve during the movement of the main slide-valve, substantially as described.

6, In slide-valve mechanism, the combination, with the main chambered slide-valve having escape-ports therein, of axed supplemental valve for said escape-ports, said supplemental valve being of sufficient width to overlap the escape-ports immediately beneath it an extent equal to the inside lap of the main slide-valve, substantially as described. v

'7. In slide-valve mechanism, the ,combination, with the main chambered slide-valve having escape-ports therein, of a supplemental valve for. said escape-ports and rods extending through the'walls of the main slide-valve and connected at their ends to the steam-chest, and connected also with the supplemental valve, substantially as described.

8. yIn slide-valve mechanism, the combination, with thecylinder having suitable steam- Ways, of a main slide-valve having exhaust or escape ports therein adapted to be brought coincident with the stearnways, and having lap-plates the lower edges of which are reduced or cut away onv the sides adjacentthe exhaust-ports, substantially as described.

' 9. In slide-valve mechanism, the combination, with a main .chambered slide-valve having exhaust yor escape ports therein, of a supplemental valve located with-in said main slide-valve, suitable mechanism extending between said supplemental valve and some relatively flxed part of the structure and adapted to control the position of said supplemental valve as the main slide-valve is operated, and a variable cut-oit for controlling the stroke of the main slide-valve, substantially as described.

CHARLES SCHMID. Witnesses: .y

GEo. P. FISHER, AJ r., JAMES H. PEIRCE. 

